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/*
* Copyright (c) 1996, 1998 University of Utah and the Flux Group.
* All rights reserved.
*
* This file is part of the Flux OSKit. The OSKit is free software, also known
* as "open source;" you can redistribute it and/or modify it under the terms
* of the GNU General Public License (GPL), version 2, as published by the Free
* Software Foundation (FSF). To explore alternate licensing terms, contact
* the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271.
*
* The OSKit is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GPL for more details. You should have
* received a copy of the GPL along with the OSKit; see the file COPYING. If
* not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
*/
/*
* Split an address map entry into two pieces
*/
#include <errno.h>
#include "amm.h"
/*
* Called whenever the AMM needs to split an entry due to conflicting flags.
* Calls the user-set split routine if available. Otherwise performs a
* simple split here. Either should split the entries and return zero or
* return non-zero if the split could not be done. A non-zero return value
* is propogated on to whoever performed the action which triggered the split
* request.
*
* ``pentry'' is a pointer to the next field of the entry previous to the
* one being split.
*
* ``entry'' is the entry to be split.
*
* ``addr'' is the address at which the split should be made. Addr is
* guarenteed to fall in the range of the entry.
*
* ``headp'' and ``tailp'' should be set to everything before addr and
* everything from addr on respectively. One or both of *headp and *tailp
* will be a new entry allocated and initialized here or in the user split
* routine. If both are new entries, we deallocate the original entry.
*
* This routine links the new entries into the map list.
*/
int
amm_split(struct amm *amm, struct amm_entry **pentry, struct amm_entry *entry,
oskit_addr_t addr, struct amm_entry **headp, struct amm_entry **tailp)
{
struct amm_entry *head, *tail;
int rc;
assert(addr >= entry->start && addr < entry->end);
if (amm->split) {
rc = (*amm->split)(amm, entry, addr, &head, &tail);
if (rc)
return rc;
} else {
tail = amm_alloc_entry(amm, addr, entry->end - addr,
entry->flags);
if (tail == 0)
return ENOMEM;
head = entry;
}
head->start = entry->start;
tail->end = entry->end;
tail->start = addr;
head->end = addr;
head->flags = entry->flags;
tail->flags = entry->flags;
tail->next = entry->next;
head->next = tail;
*pentry = head;
if (head != entry && tail != entry)
amm_free_entry(amm, entry);
*headp = head;
*tailp = tail;
return 0;
}
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